This proposal is for an additional five years of support for an existing NIDA Drug Dependence Epidemiology Training Program at Johns Hopkins University, now in its ninth year of competitively reviewed support by NIDA. The long term goal of this training program is to increase the number and quality of quantitatively adept epidemiologists and public health scientists with a career commitment for NIDA's mission in relation to epidemiology and prevention research. During a 4-5 year period of study, predoctoral trainees earn the PhD degree by completing required coursework, research apprenticeships, field research, and examinations, followed by completion of thesis research and final defense of a monograph-length thesis representing significant contributions of new scientific evidence with ramifications for theory. Postdoctoral trainees complete a more individualized program of postgraduate research training, typically lasting 2-3 years, with a greater balance of research collaboration with program faculty, through which the PDF fellows begin to assemble a portfolio of first-authored, published scientific articles, and complete drafts of their own investigator-initiated NIDA grant award applications or career development plans. The proposed plan for research training builds from the program's previously approved research training plan, with refinements that reflect accumulating experience during the research training process. Although the number and diversity of training program faculty has increased since the time of the last competitive review, there is no requested increase in the number of trainees. As proposed at that time, support for a total of five predoctoral trainees and five postdoctoral trainees is requested.